+
+ # lookup vt to build layout with
+ var vts = new HashMap[MClass, Set[MVirtualTypeProp]]
+ for mclass in mclasses do
+ vts[mclass] = new HashSet[MVirtualTypeProp]
+ for mprop in self.mainmodule.properties(mclass) do
+ if mprop isa MVirtualTypeProp then
+ vts[mclass].add(mprop)
+ end
+ end
+ end
+
+ # vt coloration
+ var vt_coloring = new MPropertyColorer[MVirtualTypeProp](mainmodule, class_colorer)
+ var vt_layout = vt_coloring.build_layout(vts)
+ self.vt_tables = build_vt_tables(mclasses, vt_layout)
+ self.vt_layout = vt_layout
+ end
+
+ fun build_vt_tables(mclasses: Set[MClass], layout: Layout[MProperty]): Map[MClass, Array[nullable MPropDef]] do
+ var tables = new HashMap[MClass, Array[nullable MPropDef]]
+ for mclass in mclasses do
+ var table = new Array[nullable MPropDef]
+ # first, fill table from parents by reverse linearization order
+ var parents = new Array[MClass]
+ if mainmodule.flatten_mclass_hierarchy.has(mclass) then
+ parents = mclass.in_hierarchy(mainmodule).greaters.to_a
+ self.mainmodule.linearize_mclasses(parents)
+ end
+ for parent in parents do
+ if parent == mclass then continue
+ for mproperty in self.mainmodule.properties(parent) do
+ if not mproperty isa MVirtualTypeProp then continue
+ var color = layout.pos[mproperty]
+ if table.length <= color then
+ for i in [table.length .. color[ do
+ table[i] = null
+ end
+ end
+ for mpropdef in mproperty.mpropdefs do
+ if mpropdef.mclassdef.mclass == parent then
+ table[color] = mpropdef
+ end
+ end
+ end
+ end
+
+ # then override with local properties
+ for mproperty in self.mainmodule.properties(mclass) do
+ if not mproperty isa MVirtualTypeProp then continue
+ var color = layout.pos[mproperty]
+ if table.length <= color then
+ for i in [table.length .. color[ do
+ table[i] = null
+ end
+ end
+ for mpropdef in mproperty.mpropdefs do
+ if mpropdef.mclassdef.mclass == mclass then
+ table[color] = mpropdef
+ end
+ end
+ end
+ tables[mclass] = table
+ end
+ return tables